This invention deals with timers, and more specifically with appliance cycle timer control mechanisms and drive mechanisms.
As the variety of demands made upon modern appliances has increased, so have the requirements made upon appliance cycle timers. For example, modern washing machines capable of washing various types of synthetic fabrics must be able to follow relatively complex washing cycle instructions in order to wash such synthetic fabrics properly. Appliances must be capable of carrying out such cycles without being attended by an operator.
As the cycle timer requirements have become more complex and demanding, cycle timers have, of course, become more complex to manufacture, adjust and install in the appliances. This increased complexity has resulted in increased cost. Further, in order to house the necessary equipment to achieve the complex cycles demanded, it has been necessary either to increase the size of appliance timers or, if the external size of the timer is required to remain constant, to decrease the size of the various internal timer components. Such a decrease in size can result in more fragile timer internal components which are more susceptible to breakage during appliance operation. Additionally such small components are frequently more expensive to manufacture and assemble, further adding to appliance cost.
Miniaturization of many appliance timer components has also been limited by the increased demand which modern appliances frequently place upon such timer components as, for example, on-off switches. Many of the necessary switches in appliance timers are now required to carry higher currents than they have in past appliances due to the increased work which the appliances are required to do. For example, the larger washing machines of today must carry larger loads of washing through a number of washing and spinning cycles. The size of the wash load often requires that the electric motor used in the washer be a higher current motor. Motor current may have to be switched several times by on-off switches housed within the appliance timer during the washing cycle.